Manganese rotary bit



Sept. :15, 1925.

W. L. HOWLETT ET AL,

MANGANESE ROTARY BIT Filed April 2, 1924 .[77 Vet/22 0 7 6: mv zwz, Z2 )Vowle,

Patented Sept. 15, 1925. I

UNITED STATES PATENT OFFICE.

WILLIAM L. HOWLETT AND JOHN W. HEASTON, OF HUNTINGTON CALIFORNIA.

MANGANESE Application filed A ril 2,

To all whom it may concern:

Be it known that we,--WVILLtAM L. How- LETT and JOHN W. HnAsToN, citizens of the United States, residing at Huntington Beach, in the county 'of Los Angelesand State of California, have invented new and useful Improvements in Manganese Rotary Bits, of which the following is a specification.

This invention relates to drilling apparatus and it has for one of its objects the provision of an improved rotary drill bit.

A further object of this invention is the provision of a drill bit having blades formed to continuously present a suitable cutting edge without-necessity for resharpening.

A still further object of this invention is the provision of a threadless tool joint for securing to a holder a rotary drill bit made entirely of a metal which is too hard to machine.

Rotary drill bits have heretofore been made of steel soft enough to be machined. Such bits, however, quickly lost their cutting edges and had to be frequently resharpened. Attempts have been made to overcome this handicap by tipping the cutting edges of the blades with manganese steel. This procedure, however, has re sulted in destroying the temper of the bit,

- thereby diminishing the hardness.

According to our invention, however, we make a rotary drill bit entirely of a very hard metal which is too hard to machine and must' be cast. Such steel may be,'for example, manganese steel. Thus we overcome the above mentioned difi'iculties of the prior art; j

Naturally the blades of the drill bit, al-' though made of the hardest kind of steel, .gradually wear away; but to avoid resharpening, we form our improved bit so that the blades always present a satisfactory cutting edge. A

By making the bit of a metal which is too hard to machine, it'is practically necessary to provide a threadless tool joint between the bit and its holder. We have therefore provided such a joint which will hereinafter be described.

BEACH, 1

ROTARY BIT.

1924., Serial No. 705,630.

accompanying drawings, in which:

Figure 1 is an elevational view of a reamer, partly brokenaway, in combination with a drill bit of our invention,

Fig. 2 is an elevational View of a reamer, partly in section, this view being similar to F ig. 1, but taken from a different angle, Fig. 3 is a bottom plan view of Fig. 1, Fig. 4 is a section taken on line 14: of F e- Fig. 5 is a section taken on line 5-5 of Fig. 1, and

Fig. 6 is a longitudinal section of a holder with an elevational View of a drill bit, partly in section, secured to the holder.

Referring to the drawings fora more detailed description thereof, the numeral 10 indicates a reamer of cruciform cross section, as shown in Fig. 4, having blades 11 and, fiutings 12. The upper end of the reamer is provided with a threaded tapered shank 13 above a collar 14. The upper end of the reamer 10 is provided with a vertical aperture 15, apertures 16 communicating with the aperture 15 at the lower end thereof and terminating in the upper portions .of the flutings 12; Apertures 15 and 16 form a passageway for water introduced to irrigate the hole which is being drilled. The lower ends of the flutings 12 are bulged outwardly, as shown at 17 in Fig. 2. A

circular tapered vertical recess 18 is formed in the lower'end of'the reamer 10, which has a portion 19 extending below the blades 11. Lateral apertures 21 are formed in the bulged or. convex .portions 17 of the flutings 12 and extend inwardly to communicate with the tapered recess 18. The apertures 21 are threaded and they are enlarged at their outer ends.

The numeral 22 indicates a drill bit of manganese or other very hard steel and comprises a circular tapered shank 23 which engages the tapered recess '18 of the reamer, but having a smaller taper than the t recess 18 so that the upper end of the shank does not contact with the upper end of the recess 18, thereby having a wedging action and producing a lateral thrust. The shank 23 is provided with recesses 25 opposite the apertures 21 and receive the ends of thread-' ed bolts 26 which pass through the apertures 21, and the heads of which are countersunk in'the convex portions 17 of the reamer. The bolts 26 thus secure the bit to the reamer and prevent the rotation of the one relative to the other. The bit 22 comprises four helical blades 27, the upper and inner portions of which are provided on one side thereof with recesses 28 which are engaged by portions 30 of the lower end 19 of the reamer 10. The upper ends 27 of .the blades 27 adjacent the recesses' 28 fit into notches 29 which are cut into the lower end, portion 19 of the reamer. Engagement of the parts 27 a of the blades 27 with the notches 29 provides additional means for securing the bit to the reamer and preventing rotation of the one relative to the other.

The shank 23 of the bit is provided with a vertical aperture 23*, from the lower end of which passageways 32 extend to the outer faces of the blades 27. The apertures 23 and'32 are not necessary when the bit is used with a reamer, but are employed when the bit is used without a reamer and is held'in a holder 33, as shown in Fig. 6. The holder 33 is secured to' the bit 22 in the same manner by which the reamer 10 is-securedto the bit. The holder 33 is provided with a vertical passageway 34 which communicates with the aperture-23 formed in. the shank of the bit.

The blades 27 which may be four in number, are 90 degrees apart, and, as stated above, are vertically helical. The lower edges 27 of the blades are concavo-convex,

as shown in- Fig. 3. The outer portions of the edges 27 are horizontal while the inner portions rise at an angle from the horizontal, as shown in Figs. 1, 2 and 6.

While we have herein described one form of our invention, modifications thereof ma be devised without departing from the spirit thereof and it is to be understood that such modifications come within the scope of this invention.

What is claimed is:

' 1. A rotary drill bit comprising a shank I having .lateral recesses adapted to be engaged by a holdin bolt and a plurality of blades of helical drm, each blade having a recess formed therein adapted to engage notches in a holding element.

12. A rotarydrill bit comprising a shank hav'ing lateral recesses adapted to be engaged by a holding bolt and a plurality. of blades of helical form, each blade having a recess formed therein adapted to engage notches in a holding element, and having an aperture communicating with an aperture' in the shank.

3. The combination with a holder having a tapered longitudinal recess and lateral apertures communicating with said recess of a bit made entirely of a metal which is too hard to machine, said bit having a tapered shank adapted to engage said longitudinal recess, said shank having lateral recesses, one for each lateral aperture in said holder, fastening means passing through the lateral apertures in said holder into the lateral recesses in said shank, said bit having a plurality of cutting blades each having a form adapted to continuously present suitable cutting edges until the blades have been worn out.

4. The combination with a holder ha'ving a tapered longitudinal recess and lateral apertures communicating with said recess of a bit made entirelyof a metal which is too hard to machine, said bithaving a tapered shank adapted to engage said longitudinal recess, said shank having lateral recesses, one for each lateral aperture in said holder, fastening means passing through the lateral apertures in said holder into the'later al recesses in said shank, said bit having a plurality of cutting blades,

each having a form adapted to continuously present suitable cutting edges until the blades have been worn out, each blade having an aperture communicating with an aperture in said shank to provide a water passage.

5. The combination with a holder having a tapered longitudinal recess. and lateral apertures communicating with said recess of a bit made entirely of a metal which is too hard to machine, said.bit having a tapered shank adapted to engage said longitudinal recess, said shank having lateral recesses, one for each late'ralaperture in said holder, fastening means passing through the lateral apertures in said holder into the lateral recesses in said shank, said bit having a plurality of cutting blades,

each having a form adapted to continuously present suitable cutting edges until the blades have been worn out, said holder and said bit being further prevented from into the lateral recesses in said shank, said bit having a plurality of cutting blades, formed on said holder and engaging reeach having a form adapted to continuously cesses formed in said blades. present suitable cutting edges until the In testimony whereof We have signed our 10 blades have been Worn out, said holder and names to this specification.

5 said bit being further prevented from rotating relative to each other by interlock- WILLIAM L. HOWLETT. ing tongues and recesses, said tongues being JOHN W. HEASTON. 

